Combustor support structure

ABSTRACT

A combustor support structure of the present invention supports, at a predetermined position of a fixation member, a combustor having a combustion section which burns supplied fuel and air, and an exhaust pipe which discharges outside, combustion gas generated by burning the fuel and air. The combustor support structure includes: a first fixing section provided in the combustor; a second fixing section provided in the fixation member and fixed to the first fixing section; a first stress-absorbing section provided in the combustor; a second stress-absorbing section provided in the fixation member and connected to the first stress-absorbing section; and a stress-absorbing member interposed between the first stress-absorbing section and the second stress-absorbing section, and absorbing stress caused by thermal expansion of the combustor.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a combustor support structure which supports a combustor at a predetermined position.

2. Description of the Related Art

Japanese Patent Application Laid-Open No. 2002-364849 discloses a conventional combustor. This combustor includes an air passage through which air is supplied into the combustor, and a fuel nozzle which is disposed in the air passage and which includes an ejection opening through which fuel is ejected. Fuel and air supplied into the air passage are mixed and burned in the combustion chamber, and generated combustion gas is discharged out through an exhaust pipe.

When actually operating such a combustor, it must be fixed to a predetermined position to maintain a stable combustion state.

SUMMARY OF THE INVENTION

However, a downstream side of the combustion gas from the combustion chamber of the combustor is heated to a high temperature by combustion gas passing through the downstream side, thereby thermally expanding the combustor and the exhaust pipe. That is, the shapes of the combustor and the exhaust pipe are varied due to temperature variations caused between a state where the combustor is stopped and is sufficiently cooled and a state where the combustor is operated and heated. Therefore, it is difficult to safely and reliably support the conventional combustor at a predetermined position.

The present invention has been achieved in view of the above circumstances, and it is an object of the invention to provide a combustor support structure which safely and reliably supports a combustor whose outside dimension is varied due to thermal stress caused between the stopped state and the operating state of the combustor.

According to one aspect of the present invention, there is provided a combustor support structure which supports, at a predetermined position of a fixation member, a combustor having a combustion section which burns supplied fuel and air, and an exhaust pipe which discharges outside, combustion gas generated by burning the fuel and air, the combustor support structure comprising: a first fixing section provided in the combustor; a second fixing section provided in the fixation member and fixed to the first fixing section; a first stress-absorbing section provided in the combustor; a second stress-absorbing section provided in the fixation member and connected to the first stress-absorbing section; and a stress-absorbing member interposed between the first stress-absorbing section and the second stress-absorbing section, the stress-absorbing member absorbing stress caused by thermal expansion of the combustor.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the accompanying drawings wherein;

FIG. 1 is a schematic view showing a structure of a combustor having a combustor support structure of the present invention;

FIG. 2 is an enlarged view of a portion of the combustor support structure of the invention, which supports the combustor; and

FIG. 3 is an enlarged view of a portion of the combustor support structure of the invention, which supports the combustor in a state where the combustor is thermally expanded.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, description will be made of embodiments of the present invention with reference to the drawings.

A combustor 10 supported by a combustor support structure 1 of this embodiment constitutes a portion of a fuel cell system of a fuel cell vehicle. The combustor 10 is supported by a sub-frame 30 as a fixation member together with a fuel cell stack and a humidifier, and is disposed on a floor of the vehicle in a state where the combustor 10 is supported by the sub-frame 30.

The combustor 10 is used for burning exhaust hydrogen included in gas discharged when a fuel cell stack is purged and for discharging the burnt exhaust hydrogen outside. Further, the combustor 10 is used such that when the fuel cell is actuated at low temperature environment, hydrogen is burned, and heat of generated combustion gas is utilized to warm equipment such as the stack.

As shown in FIG. 1, the combustor 10 includes a combustor body 11 having a combustion section 15 which burns air-fuel mixture, and a heat exchanger 20 which transmits heat of the combustion gas to cooling water of the fuel cell stack. The cooling water circulates in the heat exchanger 20 when the combustion gas generated in the combustion section 15 passes through the heat exchanger 20. A mixing section 14 which uniformly mixes air and fuel supplied into the combustor body 11 is connected to the combustor body 11. The air and fuel mixed by the mixing section 14 are sent into the combustor body 11. An air-supply port 12 to which air is supplied from an air-supply apparatus (not shown) through a cathode (not shown) of the fuel cell stack (not shown) and the humidifier (not shown) are connected to the mixing section 14. Further, a fuel-supply section 13 to which fuel is supplied from the fuel-supply apparatus (not shown) through an anode (not shown) of the fuel cell stack are connected to the mixing section 14. Air and fuel are supplied to the mixing section 14 through the air-supply port 12 and the fuel-supply section 13. An exhaust pipe 17 for discharging outside the combustion gas which passes through the heat exchanger 20 is connected to the heat exchanger 20. That is, the heat exchanger 20 is interposed between the exhaust port 16 and the exhaust pipe 17 of the combustor 10.

In this embodiment, air is supplied to the combustor 10 from the air-supply port 12 provided on one end of the substantially cylindrical combustor body 11, and fuel is supplied to the combustor 10 from the fuel-supply section 13 provided near the air-supply port 12, and the air and fuel are uniformly mixed by the mixing section 14. Thereafter, the air-fuel mixture sent from the mixing section 14 is burned in the combustion section 15, and the combustion gas is discharged outside from the other end of the combustor body 11 through the exhaust pipe 17.

The air-supply port 12 is formed at its periphery with a body-side flange 18 as a body-side fixing section. A plurality of stud bolts 18 a project from the body-side flange 18. The humidifier (not shown) is connected to the air-supply port 12, and is fixed to the sub-frame (fixation member) 30. A fixation member-side flange as a fixation member-side fixing section is formed on a portion of the humidifier. That is, nuts (not shown) are fastened to the stud bolts 18 a, the body-side flange 18 and the fixation member-side flange are connected to each other, thereby fixing the combustor 10 to the sub-frame 30 through the humidifier.

As shown in FIG. 1, body-side stays 19 having high rigidity as body-side stress-absorbing sections are fixed near a connected portion between the exhaust pipe 17 and the heat exchanger 20 and in a substantially central portion of the exhaust pipe 17, respectively. As shown in FIG. 2 and FIG. 3, the sub-frame 30 is provided with a fixation-side stay 33 having high rigidity as a stress-absorbing section on the side of the fixation member (sub-frame). The fixation-side stay 33 is opposed to the body-side stay 19 when the combustor 10 is fixed.

A mount 40 as a stress-absorbing member includes two plates 41 having high rigidity, and an absorber 42 made of elastomer, rubber or the like having resilience and elasticity. The two plates 41 are integrally formed such as to sandwich the absorber 42. Stud bolts 41 a outwardly project from the plates 41.

The mount 40 is fastened to the body-side stay 19 and the fixation-side stay 33 by fastening nuts 41 b to the stud bolts 41 a which are inserted into mounting holes 19 a and 33 a formed in the body-side stay 19 and the fixation-side stay 33. When the temperature of the combustor 10 is low, the absorber 42 of the mount 40 is not deformed as shown in FIG. 2, and the mount 40 supports the combustor 10 while keeping the formed shape thereof. When the combustor 10 is operated and the combustion section 15 is heated, the combustion section 15 and the exhaust pipe 17 are deformed in the longitudinal direction due to thermal expansion, the absorber 42 of the mount 40 is resiliently deformed, and the mount 40 supports the combustor 10 in a state where thermal stress is absorbed as shown in FIG. 3.

As explained above, according to the combustor support structure 1 of the embodiment of the present invention, body-side fixing section (body-side flange) 18 provided on the combustor 10 and the fixation member-side fixing section (fixation member-side flange) provided on the fixation member (sub-frame) 30 are connected to each other, and the body-side stress-absorbing section (body-side stay) 19 provided on the combustor 10 and the fixation member-side stress-absorbing section (fixation-side stay) 33 provided on the fixation member 30 are connected to each other with the stress-absorbing member 40. Therefore, even when the operating combustor 10 is thermally expanded, the thermal expansion is absorbed by the stress-absorbing member 40 and thus, the thermal stress acting on the fixation member 30 and the combustor 10 can be moderated, and the combustor 10 can safely and reliably be supported.

A portion of the combustor 10 closer to the air-supply port 12 than the combustion section 15 is fixed by the body-side fixing section 18, and a portion of the combustor 10 closer to the exhaust pipe 17 than the combustion section 15 is supported by the body-side stress-absorbing section 19. Therefore, equipment and pipes disposed closer to the air-supply port 12 than the combustion section 15 need not have stress absorbing function, and the entire apparatus can be simplified.

Since the heat exchanger 20 is provided between the combustor body 11 and the exhaust pipe 17, waste heat of combustion gas is absorbed and utilized by the heat exchanger 20, the machinery efficiency is enhanced, the temperature of the combustion gas which has passed through the heat exchanger 20 is lowered, and the temperature of the exhaust pipe 17 is lowered. With this structure, heat resistance required for the stress-absorbing member 40 is moderated, various materials can be used as the stress-absorbing member 40, and the cost of the stress-absorbing member 40 can be reduced.

The absorber 42 of the present embodiment is made of elastomer, rubber or the like having resilience and elasticity, but the same effect can be obtained even if a metal thin plate is corrugated so that the resilience and elasticity can be obtained, and the combustor 10 is supported by this corrugated thin plate. If metal is used as the absorber 42, even under a temperature condition where the heat exchanger 20 is not provided and the exhaust pipe 17 is heated to high temperature and elastomer, rubber or the like can not be used, the combustor can be supported safely and reliably.

The entire content of a Japanese Patent Application No. P2003-349418 with a filing date of Oct. 8, 2003 is herein incorporated by reference.

Although the invention has been described above by reference to certain embodiments of the invention, the invention is not limited to the embodiments described above will occur to these skilled in the art, in light of the teachings. The scope of the invention is defined with reference to the following claims. 

1. A combustor support structure which supports, at a predetermined position of a fixation member, a combustor having a combustion section which burns supplied fuel and air, and an exhaust pipe which discharges outside, combustion gas generated by burning the fuel and air, the combustor support structure comprising: a first fixing section provided in the combustor; a second fixing section provided in the fixation member and fixed to the first fixing section; a first stress-absorbing section provided in the combustor; a second stress-absorbing section provided in the fixation member and connected to the first stress-absorbing section; and a stress-absorbing member interposed between the first stress-absorbing section and the second stress-absorbing section, the stress-absorbing member absorbing stress caused by thermal expansion of the combustor.
 2. A combustor support structure according to claim 1, wherein the first fixing section is provided in a portion of the combustor closer to an air-supply port than the combustion section, and the first stress-absorbing section is provided in a portion of the combustor closer to the exhaust pipe than the combustion section.
 3. A combustor support structure according to claim 1, wherein a heat exchanger which transmits heat of the combustion gas to liquid which passes through the heat exchanger when the combustion gas passes is interposed between the combustion section and the exhaust pipe.
 4. A combustor support structure according to claim 1, wherein the stress-absorbing member includes at least one of an elastomer, a rubber, and a metal thin plate corrugated to obtain resilience and elasticity. 